1. Field of the Invention
The present invention relates to a belt for a machine for the production of a fibrous web, in particular paper or cardboard, and to a method for the production of such a belt.
2. Description of the Related Art
A belt, which can be employed as the fabric of a paper machine, for example, a forming sieve or a molding sieve, is known from EP 1 690 981 A1. A sieve printing process using a rotating sieve is used to apply a polymer material onto the carrier structure to form a pattern on the known fabric, for example a woven fabric, of a paper machine. The pattern can be applied in a generally arbitrary structure onto the carrier web in order to generate a structured surface on one side of the fabric, which then produces a corresponding topography on the paper being produced with this machine during the paper production.
EP 1 690 981 A1 describes a process for the application of a pattern onto the fabric of a paper machine, whereby a polymer material used to form the pattern is dispensed in an extrusion process from an extrusion head and applied onto the surface of, for example, a woven fabric for the carrier structure. The extrusion head can, in this case, be moved however necessary across the surface of the carrier structure.
From DE 102005033066 A1 a belt for a paper machine is known, whereby two layers of materials are printed one on top of the other onto a porous carrier structure, for example a woven structure, and where the materials are printed in the form of patterns such that the second layer, in this case the upper pattern which is further away from the carrier structure, exposes in some areas the pattern of the lower layer of material. This creates areas on the carrier structure where the lower layer of material exposes parts of the surface of the carrier structure, which are at least partially covered by the second or upper layer of material, so that a kind of valve effect is achieved, which allows liquid to be drained through the two layers into the porous body of the carrier structure, but which at the same time prevents most of the back flow of the liquid.
What is needed in the art is a belt for a machine to produce a fibrous web, in particular paper or cardboard, with which the structure of the belt is improved, as well as a method to produce such a belt.